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CMSIS DSP library

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cmsis_dsp/FastMathFunctions/arm_sin_q15.c@5:3762170b6d4d, 2015-11-20 (annotated)

Committer:
mbed_official
Date:
Fri Nov 20 08:45:18 2015 +0000
Revision:
5:3762170b6d4d
Parent:
3:7a284390b0ce 
Synchronized with git revision 2eb940b9a73af188d3004a2575fdfbb05febe62b



Full URL: https://github.com/mbedmicro/mbed/commit/2eb940b9a73af188d3004a2575fdfbb05febe62b/



Added option to build rpc library. closes #1426

Who changed what in which revision?

UserRevisionLine numberNew contents of line
emilmont 1:fdd22bb7aa52 1 /* ----------------------------------------------------------------------
mbed_official 5:3762170b6d4d 2 * Copyright (C) 2010-2014 ARM Limited. All rights reserved.
emilmont 1:fdd22bb7aa52 3 *
mbed_official 5:3762170b6d4d 4 * $Date: 19. March 2015
mbed_official 5:3762170b6d4d 5 * $Revision: V.1.4.5
emilmont 1:fdd22bb7aa52 6 *
emilmont 2:da51fb522205 7 * Project: CMSIS DSP Library
emilmont 2:da51fb522205 8 * Title: arm_sin_q15.c
emilmont 1:fdd22bb7aa52 9 *
emilmont 2:da51fb522205 10 * Description: Fast sine calculation for Q15 values.
emilmont 1:fdd22bb7aa52 11 *
emilmont 1:fdd22bb7aa52 12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
emilmont 1:fdd22bb7aa52 13 *
mbed_official 3:7a284390b0ce 14 * Redistribution and use in source and binary forms, with or without
mbed_official 3:7a284390b0ce 15 * modification, are permitted provided that the following conditions
mbed_official 3:7a284390b0ce 16 * are met:
mbed_official 3:7a284390b0ce 17 * - Redistributions of source code must retain the above copyright
mbed_official 3:7a284390b0ce 18 * notice, this list of conditions and the following disclaimer.
mbed_official 3:7a284390b0ce 19 * - Redistributions in binary form must reproduce the above copyright
mbed_official 3:7a284390b0ce 20 * notice, this list of conditions and the following disclaimer in
mbed_official 3:7a284390b0ce 21 * the documentation and/or other materials provided with the
mbed_official 3:7a284390b0ce 22 * distribution.
mbed_official 3:7a284390b0ce 23 * - Neither the name of ARM LIMITED nor the names of its contributors
mbed_official 3:7a284390b0ce 24 * may be used to endorse or promote products derived from this
mbed_official 3:7a284390b0ce 25 * software without specific prior written permission.
mbed_official 3:7a284390b0ce 26 *
mbed_official 3:7a284390b0ce 27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
mbed_official 3:7a284390b0ce 28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
mbed_official 3:7a284390b0ce 29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
mbed_official 3:7a284390b0ce 30 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
mbed_official 3:7a284390b0ce 31 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
mbed_official 3:7a284390b0ce 32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
mbed_official 3:7a284390b0ce 33 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
mbed_official 3:7a284390b0ce 34 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
mbed_official 3:7a284390b0ce 35 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
mbed_official 3:7a284390b0ce 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
mbed_official 3:7a284390b0ce 37 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
mbed_official 3:7a284390b0ce 38 * POSSIBILITY OF SUCH DAMAGE.
emilmont 1:fdd22bb7aa52 39 * -------------------------------------------------------------------- */
emilmont 1:fdd22bb7aa52 40
emilmont 1:fdd22bb7aa52 41 #include "arm_math.h"
mbed_official 5:3762170b6d4d 42 #include "arm_common_tables.h"
emilmont 1:fdd22bb7aa52 43
emilmont 1:fdd22bb7aa52 44 /**
emilmont 1:fdd22bb7aa52 45 * @ingroup groupFastMath
emilmont 1:fdd22bb7aa52 46 */
emilmont 1:fdd22bb7aa52 47
emilmont 1:fdd22bb7aa52 48 /**
emilmont 1:fdd22bb7aa52 49 * @addtogroup sin
emilmont 1:fdd22bb7aa52 50 * @{
emilmont 1:fdd22bb7aa52 51 */
emilmont 1:fdd22bb7aa52 52
emilmont 1:fdd22bb7aa52 53 /**
emilmont 1:fdd22bb7aa52 54 * @brief Fast approximation to the trigonometric sine function for Q15 data.
emilmont 1:fdd22bb7aa52 55 * @param[in] x Scaled input value in radians.
emilmont 1:fdd22bb7aa52 56 * @return sin(x).
emilmont 1:fdd22bb7aa52 57 *
mbed_official 3:7a284390b0ce 58 * The Q15 input value is in the range [0 +0.9999] and is mapped to a radian value in the range [0 2*pi).
emilmont 1:fdd22bb7aa52 59 */
emilmont 1:fdd22bb7aa52 60
emilmont 1:fdd22bb7aa52 61 q15_t arm_sin_q15(
emilmont 1:fdd22bb7aa52 62 q15_t x)
emilmont 1:fdd22bb7aa52 63 {
mbed_official 5:3762170b6d4d 64 q15_t sinVal; /* Temporary variables for input, output */
mbed_official 5:3762170b6d4d 65 int32_t index; /* Index variables */
mbed_official 5:3762170b6d4d 66 q15_t a, b; /* Four nearest output values */
mbed_official 5:3762170b6d4d 67 q15_t fract; /* Temporary values for fractional values */
emilmont 1:fdd22bb7aa52 68
emilmont 1:fdd22bb7aa52 69 /* Calculate the nearest index */
mbed_official 5:3762170b6d4d 70 index = (uint32_t)x >> FAST_MATH_Q15_SHIFT;
emilmont 1:fdd22bb7aa52 71
emilmont 1:fdd22bb7aa52 72 /* Calculation of fractional value */
mbed_official 5:3762170b6d4d 73 fract = (x - (index << FAST_MATH_Q15_SHIFT)) << 9;
emilmont 1:fdd22bb7aa52 74
mbed_official 5:3762170b6d4d 75 /* Read two nearest values of input value from the sin table */
mbed_official 5:3762170b6d4d 76 a = sinTable_q15[index];
mbed_official 5:3762170b6d4d 77 b = sinTable_q15[index+1];
emilmont 1:fdd22bb7aa52 78
mbed_official 5:3762170b6d4d 79 /* Linear interpolation process */
mbed_official 5:3762170b6d4d 80 sinVal = (q31_t)(0x8000-fract)*a >> 16;
mbed_official 5:3762170b6d4d 81 sinVal = (q15_t)((((q31_t)sinVal << 16) + ((q31_t)fract*b)) >> 16);
emilmont 1:fdd22bb7aa52 82
mbed_official 5:3762170b6d4d 83 return sinVal << 1;
emilmont 1:fdd22bb7aa52 84 }
emilmont 1:fdd22bb7aa52 85
emilmont 1:fdd22bb7aa52 86 /**
emilmont 1:fdd22bb7aa52 87 * @} end of sin group
emilmont 1:fdd22bb7aa52 88 */